On the island of Cuba, there are a number of deep holes, caves flooded with water where light never penetrates.

This dark world is home to species of blind fish. Blind because their eyes have atrophied – in this opaque atmosphere, they are no longer necessary.

Some of the survivors of the Planet Earth have adapted to places like this, where, because of the lack of light, colours serve no purpose. Such beings are almost always white or transparent.

However, the vast majority of animal species depend on the sun as a source of energy, through green plants. Outside marginal worlds like this one, living beings are flooded with light, and where there is light, colours and designs develop as a means of communication with the surrounding world.

Living beings on this planet are dressed to suit the occasion. An entire code of colours is used to send messages to others, a sophisticated system of communication which everyone tries to employ to their advantage.
Strident messages of love that may be intercepted by dangerous eyes. Clan markings, bright colours inviting you to eat them, or warning you to steer clear.

Humans too, adopt colour as a means of communication. Since the beginning of time, we have used them to express our emotions and feelings. In all cultures, there are colours of love, of joy and of death.

Even in the most advanced societies, colours form an important part of our identity, both as individuals and as a group.

On the beaches of mud and sand that the receding sea leaves behind along the coast of Java, in Indonesia, lives an animal whose life revolves around colour: the fiddler crab.

When the tide goes out, they take over the beach. It is time for the males to compete for attention, and this they do by displaying the colours of their enormous claws.

It serves to attract the females, who do not have this oversized appendage. And not just any female - only those of their own species. Here on the mud flats, like rival baseball teams, each species of fiddler crab has claws of a different colour.
This system works well, and is fairly widespread among very different, distant animals, such as these anoli lizards, in the West Indies. The problem is some predators have very good eyesight when it comes to intercepting the visual signals of the anolis.

The secret is to broadcast just enough to get the message across; one word too much could prove fatal.

Often, the important thing is not so much the colours themselves, but the patterns they form. For animals that see in black and white, such as the giraffes or the zebras, the important thing is the design and the distribution of stripes and patches on their bodies.

In the north of Kenya, two species of zebra often mix: Grevy’s, with thin stripes, and Burchell’s with broader stripes. For them, the differences are as great as if the other species were buffaloes; they simply ignore each other.

For the inhabitants of New Guinea, war and tribal clashes form part of their existence, and so painting yourself in the right colours can be a matter of life or death. On this large island, around 1,000 different languages are spoken, and the members of each clan use different war paints in the frequent disputes. Within each group, the dominant colours are similar, and act like the uniforms of soldiers in a battle. Any confusion and you could be speared down by someone from your own side.

For a Papuan child, the colours of the enemy tribes represent terror and death, while those of its own clan embody peace and the home. Even if these clashes come to an end some day, the clan colours will live on in the stories they represent through dance.